The whole UI of diffmerge locks up, and my teammates were closing it down thinking it was crashing. I think it's critical for save file to occur on a separate thread and control a small progress bar. This is a huge bug.

zippo227: If you don't mind, I'm going to jump in on this one and see what I can do. Would you be willing to email me at support at sourcegear.com with a link to this thread? Since I wasn't in on the previous discussion, I would like to ask additional questions, and try to recreate the scenario.